Adam Clarke on Numbers 16:22

O God, the God of the spirits of all flesh - אל אלהי הרוחת לכל בשר El Elohey haruchoth lechol basar. This address sufficiently proves that these holy men believed that man is a being compounded of flesh and spirit, and that these principles are perfectly distinct. Either the materiality of the human soul is a human fable, or, if it be a true doctrine, these men did not pray under the influence of the Divine Spirit. In Num 27:16 there is a similar form of expression: Let the Lord, the God of the spirits of all flesh. And in Job 12:10 : In whose hand is the soul (נפש nephesh) of all living; and the spirit (רוח ruach) of all flesh of man. Are not these decisive proofs that the Old Testament teaches that there is an immortal spirit in man? "But does not רוח ruach signify wind or breath?" Sometimes it does, but certainly not here; for how absurd would it be to say, O God, the God of the breaths of all flesh!